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What is the dragon fruit?
Dragon fruit, pitahaya or pitaya is the name of the fruit produced by some American cactus species - Cactaceae botanical family . In Italy it is normally considered one of the most "fascinating" tropical fruits.
It is a tropical fruit that belongs to the VII fundamental group of foods - foods rich in vitamin C. It also contains little water, lots of soluble sugars (fructose), dietary fiber and some minerals - including sodium and calcium. In the diet it has the same function as the local fruits and can be consumed, even in different portions, by most of the general population; however, there are few exceptions, mainly related to pre-existing pathologies, which we will describe later.
The dragon fruit has a very characteristic shape; it vaguely resembles the prickly pear, but it is larger and has a unique morphology. The skin is usually red or purple or yellow, while the pulp can be red or white or yellowish. They reach considerable dimensions.
Usually, they are called dragon fruits or pitahaya those produced by the botanical genus Stenocereus, while the pitaya is more commonly used for the genus Hylocereus . The dragon fruit is grown mainly in Southeast Asia, Florida, the Caribbean, Australia and all tropical and subtropical regions of the world.
Did you know that ...
These fruits are commonly known in English as "dragon fruits", reflecting the vernacular Asian names. The pitahaya and pitaya nouns instead derive from Mexico, while in Central America and in North South America it is mainly used "pitaya roja".
Nutritional Properties
Nutritional properties of the dragon fruit
In 2018, the "Department of Agriculture of the United States" analyzed for the first time the dragon fruits imported by one producer, showing that 100 grams of pitaya contain 268 calories; 82 g are made up of carbohydrates, 4 g of protein and 11 g of vitamin C and calcium.
The dragon fruit belongs to the seventh food group - foods rich in vitamin C; it is also a source of soluble sugars, fibers and certain minerals even if, as we shall see, it is poor in water.
The nutritional properties of the dragon fruit or pitaya are interesting but still not very detailed. It has a very high energy intake, mainly provided by the concentration of sugars; the proteins are less relevant, while the lipids - of the pulp, not of the seeds - are absent or marginal.
The glucides are mainly soluble and are composed of the fructose monosaccharide and the proteins have a low biological value. The dragon fruit contains many dietary fibers. Cholesterol, lactose and gluten are absent. Histamine, purines and phenylalanine amino acid appear in scarce or almost zero amounts. It is not clear if it is a hibernating food.
The pitaya is rich in vitamin C (ascorbic acid). Regarding mineral salts, the dragon fruit seems to contain mainly calcium - but its bioavailability - and sodium - remains unknown. The fruit of the red dragon and the purple one are rich in betacyanins - antioxidant anthocyanidins.
Dragon fruit | |
Nutritional values per 100 g | Quantity' |
| Power | 268.0 kcal |
Total carbohydrates | 82.14 g |
Starch | -g |
| Simple sugars | 82.14 g |
| fibers | 1.8 g |
| Grassi | - g |
| Saturated | - g |
| Monounsaturated | - g |
| polyunsaturated | - g |
| Cholesterol | 0.0 mg |
| Protein | 3.57 g |
| water | - g |
| Vitamins | |
| Vitamin A equivalent | - RAE |
| Beta-Carotene | -μg |
| Lutein Zexanthin | -μg |
| Vitamin A | -iu |
| Thiamine or vit B1 | - mg |
| Riboflavin or vit B2 | - mg |
| Niacin or vit PP or vit B3 | - mg |
| Pantothenic acid or vit B5 | - mg |
| Pyridoxine or vit B6 | - mg |
| folate | -μg |
| Vitamin B12 or cobalamin | -μg |
| Choline | - mg |
| C vitamin | 9.2 mg |
| Vitamin D | -μg |
| Vitamin E | - mg |
| Vitamin K | -μg |
| Minerals | |
| Football | 107.0 mg |
| Iron | - mg |
Magnesium | -mg |
| Manganese | -mg |
| Phosphorus | - mg |
| Potassium | - mg |
| Sodium | 39.0 mg |
| Zinc | - mg |
| fluoride | -μg |
Dragon fruit seed oil
The fatty acid composition of the dragon fruit seed oil is as follows:
| Hylocereus costaricensis (Red-fleshed pitaya) | Hylocereus undatus (White-fleshed pitaya) | |
| Myristic acid | 0.2% | 0.3% |
| Palmitic acid | 17.9% | 17.1% |
| Stearic Acid | 5.49% | 4.37% |
| Palmitoleic acid | 0.91% | 0.61% |
| Oleic acid | 21.6% | 23.8% |
| Cis-Vaccene Acid | 3.14% | 2.81% |
| Linoleic acid | 49.6% | 50.1% |
| Linolenic acid | 1.21% | 0.98% |
Diet
Dragon fruit in the diet
The pulp of the dragon fruit does not lend itself to all diets; this is because it is very caloric and sugary. It is difficult to contextualize in the diet against overweight and metabolic pathologies, especially type 2 diabetes mellitus and hypertriglyceridemia; nevertheless, adapting the portions could constitute an occasional alternative.
No member of the pitaya is able to compromise nutritional therapy against high blood pressure, hypercholesterolemia, celiac disease, lactose intolerance and phenylketonuria. Moreover, being lacking in purines, the dragon fruit could be used in the diet against hyperuricemia and kidney stones (lithiasis) from uric acid; however, it should not be forgotten that excess fructose in the diet is able to hinder the elimination of this unwanted element from the blood. It reserves the right to understand if this food can release large amounts of histamine - as does, for example, strawberry.
Due to the lack of water the dragon fruit plays no role in the promotion of salt and water balance; in other words, it does not contribute to maintaining the body's hydration state, which is especially precarious in athletes and the elderly.
The pitaya is full of soluble fibers and can increase the feeling of fullness - even if fructose, on the other hand, does not stimulate the sense of satiety as effectively as other simple carbohydrates (eg glucose). Furthermore, the soluble fibers act positively on the metabolism modulating the absorption - reduction of the glycemic index (even if, given the sugar load, this assumes a secondary metabolic importance), reduction of cholesterol uptake - preventing constipation and all related complications - hemorrhoids, anal fissures, diverticulosis, diverticulitis, anal prolapse, certain forms of cancer etc. It should also be remembered that the fibers, particularly the soluble ones, are also excellent prebiotics and effectively nourish the bacterial flora of the colon.
The good percentage of vitamin C is very useful to support the defensive action against free radicals. Furthermore, ascorbic acid is a necessary factor for the synthesis of collagen, a protein widespread in the human body, and contributes to supporting the immune system. As far as minerals are concerned, it is difficult to establish whether the good concentration of calcium can really contribute to increasing the overall intake, since its true bioavailability is unknown.
The average recommended portion of the dragon's fruit is approximately 50 g (132 kcal).
Description
Basics of description of the dragon fruit
The dragon fruit of the genus Hylocereus can be red or purple; the color is due to betacyanins, a family of pigments that also includes betanin, the same substance that gives red color to turnips and amaranth.
The pulp of the dragon fruit is compared by some to that of the kiwi, due to the black and crunchy seeds. The taste is basically delicate, with a prevalent sweet taste and more or less acidulous depending on the variety.
Botany
Notes on the botany of the dragon fruit
The dragon fruits are produced by some cacti, therefore from plants belonging to the botanical family Cactaceae ; more precisely, they are vegetables belonging to the Stenocereus and Hylocereus genres.
Those of the genus Hylocereus originate from Mexico, Guatemala, Nicaragua, Costa Rica, El Salvador and the southern portion of North America. Today the dragon fruit is cultivated mainly in south-east Asia, Florida, the Caribbean, Australia and all regions of the tropical and subtropical world.
The dragon fruit commonly weighs from 150 to 600 grams; some can reach 1 kilogram.
Variety of dragon fruit
Variety of the genus Stenocereus
The fruit produced from botanical species of the genus S tenocereus - or pitaya aspra - is another variety of dragon fruit consumed mainly in the arid American regions. It has a more intense taste, acid and a generally refreshing taste; the pulp is more juicy.
The pitaya agria ( S. gummosus ) of the Sonoran desert has been an important source of food for the indigenous peoples of the Americas. The Seri people of north-western Mexico still collect these fruits and define the cactus "ziix ccapxl", translated as "something whose fruit is acid".
Also the fruits of similar species, such as S. queretaroensis and S. griseus - or dagger cactus - are important foods locally. The fruit of the S. thurberi - or "organ-pipe cactus", whose fruit is called "ool" by the Seris - is a sweet pitaya - sweet pitaya. It is even more sour than the fruit of the genus Hylocereus and finds some uses in traditional medicine.
Variety of the genus Hylocereus
The sweet pitaya is available in three types, all with a leathery peel, slightly leafy:
- Hylocereus undatus - pitaya blanca - produces a fruit with a pink skin and white flesh. It is the most common dragon fruit
- Hylocereus costaricensis - pitaya roja; also known as Hylocereus polyrhizus - it produces a fruit with a red skin and red flesh
- Hylocereus megalanthus - pitaya amarilla or yellow; also known as Selenicereus megalanthus - produces a fruit with a yellow skin and white pulp.
The first cacti imported from Colombia to Australia were called Hylocereus ocampensis - presumably, with red fruits - and Cereus triangularis - presumably, with yellow fruits. It is not entirely clear which species these taxons refer to, although the former is probably related to the red pitaya.
Cultivation of the dragon fruit
After careful removal of the seeds from the fruit pulp, these can be dried and stored for cultivation.
The seeds grow well in organic compost or soil mixtures, even as a pot plant. The dragon fruit cacti sprout between 11 and 14 days after superficial sowing. Being Cactaceae, when in excess they tend to become weeds. As the growth continues, these climbing plants produce additional aerial roots. It flowers once it reaches 10 pounds.
The commercial plantations of dragon fruit can also be made at a high density of 1100 and 1350 plants per hectare. The cacti can take up to five years to arrive in full commercial production, which makes from 20 to 30 tons per hectare.
Pitaya flowers hatch during the night and usually wither in the morning. For fertilization, they rely on nocturnal pollinators like bats or moths. Self-fertilization does not produce fruit in some species and, although the crossing has given rise to several "self-fertile" varieties, cross-pollination with a second plant species generally increases the production and quality of the fruit. This limits the capacity of home growers. However, plants can flower between three and six times in a year depending on growing conditions. Like other cacti, if a healthy piece of stem is broken, it can take root in the soil and become autonomous.
Plants can withstand temperatures up to 40 ° C and very short frost periods, but they do not survive long exposure to freezing temperatures. Dragon fruit cacti thrive more in USDA 10-11 (arid) areas, but can survive outdoors in zones 9a or 9b.
The genus Hylocereus has adapted to live in dry tropical climates, with a moderate amount of rain. The dragon fruits are formed on cactus trees 30-50 days after flowering and sometimes can have 5-6 harvest cycles per year. In many regions it has escaped cultivation to become a pest.
Pests and diseases of the dragon fruit
Excessive precipitation can cause flowers to fall and dragon fruit to break down. Furthermore, excessive water swelling can cause ripening of the ripened fruit.
Birds feed on these foods.
The bacterium Xanthomonas campestris causes the stems to rot quickly. Dothiorella mushrooms can cause brown spots on the fruit, but it is not a common occurrence. Other mushrooms are: Botryosphaeria dothidea, Colletotrichum gloesporioides and Bipolaris cactivora .
